Problem: Suppose a parallelogram has base length $7 \text{ cm}$ and height $3 \text{ cm}$. What is the parallelogram's area?
Answer: ${b = 7\text{ cm}}$ ${h = 3\text{ cm}}$ $21$ By moving a slice of the parallelogram, we can see that its area is equal to that of a rectangle with the same base and height. area of rectangle $ = b \times h$ $A = 7 \times 3 = 21$